scholarly journals Use of Newly Designed Primers for Quantification of Complete Ammonia-Oxidizing (Comammox) Bacterial Clades and Strict Nitrite Oxidizers in the Genus Nitrospira

2020 ◽  
Vol 86 (20) ◽  
Author(s):  
Ran Jiang ◽  
Jian-Gong Wang ◽  
Ting Zhu ◽  
Bin Zou ◽  
Dan-Qi Wang ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Water Systems ◽  
Ammonia Oxidizers ◽  
Specific Primer ◽  
High Coverage ◽  
Nitrite Oxidizing Bacteria ◽  
Nitrite Oxidoreductase ◽  
Primer Sets ◽  
Drinking Water Systems

ABSTRACT Complete ammonia-oxidizing (comammox) bacteria play key roles in environmental nitrogen cycling and all belong to the genus Nitrospira, which was originally believed to include only strict nitrite-oxidizing bacteria (sNOB). Thus, differential estimation of sNOB abundance from that of comammox Nitrospira has become problematic, since both contain nitrite oxidoreductase genes that serve as common targets for sNOB detection. Herein, we developed novel comammox Nitrospira clade A- and B-specific primer sets targeting the α-subunit of the ammonia monooxygenase gene (amoA) and a sNOB-specific primer set targeting the cyanase gene (cynS) for quantitative PCR (qPCR). The high coverage and specificity of these primers were checked by use of metagenome and metatranscriptome data sets. Efficient and specific amplification with these primers was demonstrated using various environmental samples. Using the newly designed primers, we successfully estimated the abundances of comammox Nitrospira and sNOB in samples from two chloramination-treated drinking water systems and found that, in most samples, comammox Nitrospira clade A was the dominant type of Nitrospira and also served as the primary ammonia oxidizer. Compared with other ammonia oxidizers, comammox Nitrospira had a higher abundance in process water samples in these two drinking water systems. We also demonstrated that sNOB can be readily misrepresented by an earlier method, calculated by subtracting the comammox Nitrospira abundance from the total Nitrospira abundance, especially when the comammox Nitrospira proportion is relatively high. The new primer sets were successfully applied to comammox Nitrospira and sNOB quantification, which may prove useful in understanding the roles of Nitrospira in nitrification in various ecosystems. IMPORTANCE Nitrospira is a dominant nitrite-oxidizing bacterium in many artificial and natural environments. The discovery of complete ammonia oxidizers in the genus Nitrospira prevents the use of previously identified primers targeting the Nitrospira 16S rRNA gene or nitrite oxidoreductase (nxr) gene for differential determination of strict nitrite-oxidizing bacteria (sNOB) in the genus Nitrospira and among comammox bacteria in this genus. We designed three novel primer sets that enabled quantification of comammox Nitrospira clades A and B and sNOB with high coverage, specificity, and accuracy in various environments. With the designed primer sets, sNOB and comammox Nitrospira were differentially estimated in drinking water systems, and we found that comammox clade A predominated over sNOB and other ammonia oxidizers in process water samples. Accurate quantification of comammox Nitrospira and sNOB by use of the newly designed primers will provide essential information for evaluating the contribution of Nitrospira to nitrification in various ecosystems.

scholarly journals Microbial Nitrogen Metabolism in Chloraminated Drinking Water Reservoirs

mSphere ◽  
2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Sarah C. Potgieter ◽  
Zihan Dai ◽  
Stephanus N. Venter ◽  
Makhosazana Sigudu ◽  
Ameet J. Pinto
Keyword(s):  
Nitric Oxide ◽  
Drinking Water ◽  
Nitrogen Metabolism ◽  
Distribution Systems ◽  
Water Systems ◽  
Nitrite Reduction ◽  
Water Utilities ◽  
Water Reservoirs ◽  
Nitrite Oxidizing Bacteria ◽  
Drinking Water Systems

ABSTRACT Ammonia availability due to chloramination can promote the growth of nitrifying organisms, which can deplete chloramine residuals and result in operational problems for drinking water utilities. In this study, we used a metagenomic approach to determine the identity and functional potential of microorganisms involved in nitrogen biotransformation within chloraminated drinking water reservoirs. Spatial changes in the nitrogen species included an increase in nitrate concentrations accompanied by a decrease in ammonium concentrations with increasing distance from the site of chloramination. This nitrifying activity was likely driven by canonical ammonia-oxidizing bacteria (i.e., Nitrosomonas) and nitrite-oxidizing bacteria (i.e., Nitrospira) as well as by complete-ammonia-oxidizing (i.e., comammox) Nitrospira-like bacteria. Functional annotation was used to evaluate genes associated with nitrogen metabolism, and the community gene catalogue contained mostly genes involved in nitrification, nitrate and nitrite reduction, and nitric oxide reduction. Furthermore, we assembled 47 high-quality metagenome-assembled genomes (MAGs) representing a highly diverse assemblage of bacteria. Of these, five MAGs showed high coverage across all samples, which included two Nitrosomonas, Nitrospira, Sphingomonas, and Rhizobiales-like MAGs. Systematic genome-level analyses of these MAGs in relation to nitrogen metabolism suggest that under ammonia-limited conditions, nitrate may be also reduced back to ammonia for assimilation. Alternatively, nitrate may be reduced to nitric oxide and may potentially play a role in regulating biofilm formation. Overall, this study provides insight into the microbial communities and their nitrogen metabolism and, together with the water chemistry data, improves our understanding of nitrogen biotransformation in chloraminated drinking water distribution systems. IMPORTANCE Chloramines are often used as a secondary disinfectant when free chlorine residuals are difficult to maintain. However, chloramination is often associated with the undesirable effect of nitrification, which results in operational problems for many drinking water utilities. The introduction of ammonia during chloramination provides a potential source of nitrogen either through the addition of excess ammonia or through chloramine decay. This promotes the growth of nitrifying microorganisms and provides a nitrogen source (i.e., nitrate) for the growth for other organisms. While the roles of canonical ammonia-oxidizing and nitrite-oxidizing bacteria in chloraminated drinking water systems have been extensively investigated, those studies have largely adopted a targeted gene-centered approach. Further, little is known about the potential long-term cooccurrence of complete-ammonia-oxidizing (i.e., comammox) bacteria and the potential metabolic synergies of nitrifying organisms with their heterotrophic counterparts that are capable of denitrification and nitrogen assimilation. This study leveraged data obtained for genome-resolved metagenomics over a time series to show that while nitrifying bacteria are dominant and likely to play a major role in nitrification, their cooccurrence with heterotrophic organisms suggests that nitric oxide production and nitrate reduction to ammonia may also occur in chloraminated drinking water systems.

scholarly journals The Water Safety Plan Approach: Application to Small Drinking-Water Systems—Case Studies in Salento (South Italy)

2021 ◽  
Vol 18 (8) ◽  
pp. 4360
Author(s):  
Francesca Serio ◽  
Lucia Martella ◽  
Giovanni Imbriani ◽  
Adele Idolo ◽  
Francesco Bagordo ◽  
...  
Keyword(s):  
Drinking Water ◽  
Case Studies ◽  
Distribution Systems ◽  
Water Systems ◽  
Water Safety ◽  
Quality Of Water ◽  
Safety Plan ◽  
Water Safety Plan ◽  
Drinking Water Systems

Background: The quality of water for human consumption is an objective of fundamental importance for the defense of public health. Since the management of networks involves many problems of control and efficiency of distribution, the Water Safety Plan (WSP) was introduced to address these growing problems. Methods: WSP was applied to three companies in which the water resource assumes central importance: five water kiosks, a third-range vegetable processing company, and a residence and care institution. In drafting the plan, the terms and procedures designed and tested for the management of urban distribution systems were applied to safeguard the resource over time. Results: The case studies demonstrated the reliability of the application of the model even to small drinking-water systems, even though it involved a greater effort in analyzing the incoming water, the local intended use, and the possibilities for managing the containment of the dangers to which it is exposed. This approach demonstrates concrete effectiveness in identifying and mitigating the dangers of altering the quality of water. Conclusions: Thanks to the WSP applied to small drinking-water systems, we can move from management that is focused mainly on verifying the conformity of the finished product to the creation of a global risk assessment and management system that covers the entire water supply chain.

scholarly journals Occurrence of Lead and Other Toxic Metals Derived from Drinking-Water Systems in Three West African Countries

2021 ◽  
Vol 129 (4) ◽  
Author(s):  
Michael B. Fisher ◽  
Amy Z. Guo ◽  
J. Wren Tracy ◽  
Sridevi K. Prasad ◽  
Ryan D. Cronk ◽  
...  
Keyword(s):  
Drinking Water ◽  
Toxic Metals ◽  
Water Systems ◽  
West African ◽  
African Countries ◽  
Drinking Water Systems

scholarly journals Disinfection exhibits systematic impacts on the drinking water microbiome

2019 ◽  
Author(s):  
Zihan Dai ◽  
Maria C. Sevillano-Rivera ◽  
Szymon T. Calus ◽  
Q. Melina Bautista-de los Santos ◽  
A. Murat Eren ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Distribution ◽  
Microbial Growth ◽  
Glyoxylate Cycle ◽  
Water Systems ◽  
Chemical Compositions ◽  
Functional Potential ◽  
Decay Products ◽  
The Impact ◽  
Drinking Water Systems

ABSTRACTLimiting microbial growth during drinking water distribution is achieved either by maintaining a disinfectant residual or through nutrient limitation without the use of a disinfectant. The impact of these contrasting approaches on the drinking water microbiome is not systematically understood. We utilized genome-resolved metagenomics to compare the structure, metabolic traits, and population genomes of drinking water microbiomes across multiple full-scale drinking water systems utilizing these two-distinct microbial growth control strategies. Microbial communities cluster together at the structural- and functional potential-level based on the presence or absence of a disinfectant residual. Disinfectant residual concentrations alone explained 17 and 6.5% of the variance in structure and functional potential of the drinking water microbiome, respectively, despite including samples from multiple drinking water systems with variable source waters and source water communities, treatment strategies, and chemical compositions. The drinking water microbiome is structurally and functionally less diverse and less variable across disinfected systems as compared to non-disinfected systems. While bacteria were the most abundant domain, archaea and eukaryota were more abundant in non-disinfected and disinfected systems, respectively. Community-level differences in functional potential were driven by enrichment of genes associated with carbon and nitrogen fixation in non-disinfected systems and γ-aminobutyrate metabolism in disinfected systems which may be associated with the recycling of amino acids. Metagenome-assembled genome-level analyses for a subset of phylogenetically related microorganisms suggests that disinfection may select for microorganisms capable of using fatty acids, presumably from microbial decay products, via the glyoxylate cycle. Overall, we find that disinfection exhibits systematic and consistent selective pressures on the drinking water microbiome and may select for microorganisms able to utilize microbial decay products originating from disinfection inactivated microorganisms.

scholarly journals Detection of Microcystins in Lake Manatee and Lake Washington – Two Florida Drinking Water Systems

2021 ◽  
Author(s):  
Rajesh Melaram ◽  
Brandon Lopez-Dueñas
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Surface Water Quality ◽  
Well Being ◽  
Water Systems ◽  
Enzyme Linked Immunosorbent Assay ◽  
Water Supplies ◽  
Intrinsic Nature ◽  
Lake Washington ◽  
Drinking Water Systems

Clean, fresh, and safe drinking water is essential to human health and well-being. Occasionally, chemical pollutants taint surface water quality used for consumption. Microcystins (MCs) are toxic heptapeptides produced by freshwater cyanobacteria. These secondary metabolites can reach hazardous concentrations, impairing surface drinking water supplies. Inconsistent screening of MCs is not uncommon in Florida waters as no provisional guidance value is established to protect public health. The occurrence of MCs in Lake Manatee and Lake Washington was monitored over the potential peak algae bloom season (June-August). An indirect competitive enzyme-linked immunosorbent assay (icELISA) quantified total MCs in two drinking water systems. Varied concentrations occurred between June and July, whereas concentrations peaked in August. Overall, MC prevalence was higher in Lake Manatee than Lake Washington. Colorimetric assays measured phosphate and nitrite in environmental water samples. Phosphate and nitrite concentrations strongly correlated with total MCs (p < 0.01). The results indicate the intrinsic nature of environmental MCs in surface drinking water supplies and the need to examine hepatotoxin dynamics to preserve drinking water quality in community served areas.

Comammox in drinking water systems

2017 ◽  
Vol 116 ◽  
pp. 332-341 ◽  
Author(s):  
Yulin Wang ◽  
Liping Ma ◽  
Yanping Mao ◽  
Xiaotao Jiang ◽  
Yu Xia ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Systems ◽  
Drinking Water Systems
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